Compared with non-malignant thyroid follicular cells, malignant thyroid follicular cells were enriched in cytokine–cytokine receptor interaction, PI3K/Akt signaling pathway, MAPK signaling pathway, tumor necrosis factor (TNF) signaling pathway, focal adhesion, proteoglycans in cancer, chemokine signaling pathway, transcriptional misregulation in cancer, and cell adhesion molecules (Figure 2D and Supplementary Table S1). Here, PIK3CA is linked to cancer.